The present invention relates to specialized equipment for medical use. The present invention particularly relates to tracheal tubes which are used to introduce gasses or vapors along the trachea, such as by an anesthesiologist during the administration of anesthesia to a patient undergoing surgery.
As early as 1889, a straight tracheal tube was reported as being used to administer anesthesia. From that time, tracheal tubes have been designed of various shapes and curvatures and have been made of either rigid or flexible materials. Flexible tubes have the advantage of automatically conforming to the shape and curvature of the body in individual instances, but have the disadvantage of dangerous kinking which may cause critical stoppage of gas or vapor flow through the tube.
Known tracheal tubes include the so-called "Oxford tube", which has a widely curved, right-angle bend adapted for placement in the trachea and posterior pharynx, and is formed of non-kinking, flexible tubing. A similarly constructed tube having a sigmoid curve is shown in U.S. Pat. No. 3,363,629, to Kuhn. Neither of these tubes are entirely satisfactory.
When surgery is to be performed on the head, face, mouth or neck areas of a patient, it is desirable to provide a maximum amount of access to those areas. Therefore, placement of the anesthesia circuit becomes very important.
The anesthesia circuit is normally comprised of a tracheal tube, an anesthesia supply and means for connecting the tracheal tube to the anesthesia supply. Several different arrangements of the anesthesia circuit have been used in an attempt to maximize access to the surgical area.
Tracheal tubes may be designed so as to be either inserted through the oral or nasal passages of a patient. The choice of using an oral or nasal tracheal tube is generally dependent on the type of medical or surgical procedure to be performed.
Oral tracheal tubes are introduced through the patient's mouth and directed into the patient's trachea. Oral tracheal tubes are generally preferred over nasal tracehal tubes because it is felt thay are easier to place correctly in the trachea.
A nasal tracheal tube is a tube which is introduced through the patient's nose and directed into the patient's trachea. Nasal tracheal tubes are used when the surgeon performs surgery in the mouth, when the mouth must be closed during surgery, or when the patient must continue to be mechanically ventilated for long periods after the surgical procedure.
One known type of tracheal tube is designed to have a proximal end which terminates near its exit from the mouth or nose of a patient. Connector tubing is then used to connect the tracheal tube to the anesthesia supply.
A connector for a tracheal tube of this type is described in U.S. Pat. No. 5,024,220 to Holmgreen et al. The connector described in Holmgreen et al comprises a section of flexible corrugated tubing which has a distal end adapted to fit into the lumen of an intubated nasal tracheal tube, and a proximal end adapted to receive a standard anesthesia tubing connector. The connector described in Holmgreen et al is intended to facilitate access to the mouth and face of a patient and to reduce the possibility of trauma or tissue damage during intubation and use.
However, the connector and tracheal tube combination of Holmgreen et al has several disadvantages. For example, the connector of Holmgreen et al requires numerous connection points to complete the anesthesia circuit. Each connection point of this type, i.e. non-permanent, carries the risk of leakage or disconnection during use, thereby compromising the anesthesia circuit. In addition, the corrugated tubing used as the connector has a rough, ribbed inner surface, which makes it difficult to pass accessory equipment, such as a fiber optic scope or suction catheter, for example, through the tube. In particular, passage of such a device may often be impeded by the corrugated ribbing of the connector, thereby requiring remanuevering of the device, as well as use of force to get the device fully through the corrugated segment. Use of such force may cause trauma to the patient's mucosa and trachea, as well as possibly compromising the anesthesia circuit by dislodging the tracheal tube from its proper intubated position. Another disadvantage of using corrugated connector tubing, as described in Holmgreen et al, is that the corrugated tubing possesses shape retention properties. Therefore, the corrugated tubing tends to return to its preformed, non-bent or non-curved state. This can be disadvantageous because the tube in attempting to return to its preformed shape, may loosen or pull free from surgical tape intended to hold it in a secure position. Further, the force exerted to hold the corrugated segment in a curved position, i.e. along the patient's face, is transmitted to the proximal end of the tracheal tube and may cause necrosis at the naris.
A second type of tracheal tube has as preformed proximal end which includes an extension segment that extends from the point of exit from the nose or mouth of the patient and is bent or curved in such a manner to extend along the patient's face to a connection with the anesthesia circuit.
A known tracheal tube for either oral or nasal use and having a preformed proximal end segment, is described in U.S. Pat. No. 3,964,488 to Ring et al. This tube includes a distal or patient end portion which is curved so as to conform to the shape of the trachea and posterior pharynx, an intermediate portion connected to the distal end portion, and a proximal or machine end portion which includes an abrupt bend of no greater than 90.degree., such that the proximal end portion will be located exteriorly of the patient, and will extend along the face of the patient when the tube is installed for use. In those embodiments where the tube is intended for oral use, the distal or patient end portion extends in the same general direction as the proximal or machine end portion. In those embodiments where the tube is intended for nasal use, the distal or patient end portion extends in the generally opposite direction to the proximal or machine end portion. This tube allows the placement of connectors and adapters away from the surgery area and thereby provides increased access to the head and neck area during surgery. Also, this tube reduces the risk of kinking at the bend location, and helps to prevent injury to the patient from pressure by relatively heavy connectors and adapters attached to the tube.
However, preformed tubes of this type exhibit several disadvantages also. In particular, the curve of the preformed tubes must be controlled accurately to correspond with the anatomy of the patient. While standard sizes and shapes will be appropriate for most patients, there are many occasions when the predetermined curve will leave the proximal extension at an improper distance from the facial region. This may result in excessive pressure being exerted on sensitive tissue in the nasal and oral regions, as well as to the mucosa and trachea at the distal end of the tracheal tube. To avoid such problems, removal of the tracheal tube and re-intubation may be required, which increases the risk of injury or trauma to the patient. If the distance between the face and tube is too great, the assembly may become quite bulky and interfere with surgical access to the operative field.
Also, the preformed tracheal tubes do not allow for shifting of the tube during an operation, but rather may be positioned in only one way. Therefore, full access to the operative field may be compromised.
Therefore, there remains a need for a tracheal tube which allows even greater access to the head and neck of a patient during surgery, and which allows for changing placement of the proximal end of the tube during surgery, without increasing the risk of injury or trauma to the patient.